Ever since Knoppix create the Live bootable CD for the Knoppix Linux, all sorts of bootable CD/DVDs have flooded the internet. There are obviously the bootable Live CD/DVDs for all many different flavors of the Linux operating system, then there are antivirus repair disks, hard disk erasing disks, partition manager disks, hard disk cloning disks and many more. All of these bootable CD/DVDs are available for free to be downloaded from the internet in the popular ISO image format. But if you do not have a blank CD/DVD ready for use, then you can create a bootable USB disk using your USB pen drive and the free UNetbootin software.
UNetbootin is a cross platform bootable USB creator and can run on Windows, Linux and Mac. It supports all the popular Linux distributions including Ubuntu, Mint, Debian, Fedora, openSUSE etc., in addition to antivirus repair disks like Kaspersky Rescue CD, F-Secure Rescue CD, Dr. Web Antivirus Repair Disk and many other. In general, it supports any ISO image designed to boot using the Linux OS.
Although UNetbootin supports downloading the supported ISO images from the internet directly, it is suggested that you download the ISO images using some other download manager and then use the ISO image. This way you can re-use the ISO image later on.
In the first screen of the UNetbootin, you have to choose whether you want to download the ISO image from the internet or use the already downloaded ISO image. You also have to choose the USB disk drive and whether you want to preserve space to save files across reboots.
As soon as you click on the OK button, it starts to download the files, extract them to the target USB drive and install the bootloader. Progress for all these steps is shown in the UNetbootin window.
Finally, when everything has been done, a message is shown that the installation is complete which means that your live bootable USB disk is ready to be used. Now you can reboot your PC, choose the USB disk to boot and start using it.
Conclusion: Although it exclusively supports only Linux based bootable disks, UNetbootin can create live bootable USB disks for all the popular Linux based bootable ISO images. In addition to all the popular Linux distros, it also supports many antivirus rescue disks.
You can download UNetbootin from http://unetbootin.sourceforge.net/.